Refs ZEN-5557. Event mgmt w/ non-global permission

Modify ActionButton to keep track of state of three booleans independently: permitted, filtered, externallyDisabled. This is basically the same as before, but with the addition of the "filtered" state. Basically, "filtered" (if true) means that we've already filtered down to only those things the user has permission for (and so "permitted" is moot).

For users without a global role, add a "Show only actionable events" checkbox item to the Event panel "Configure" menu. When it is checked, the user is allowed to acknowledge/close/etc events that they select in the event console.

We do not enable reclassification for users without global permission.

See: http://jira.zenoss.com/jira/browse/ZEN-5557